Bur-removing machine.



S. THOOD.

BUR REMOVING MAEHINE.

APPLICATION FILED FEB-2h 1914.

Patented m0. 4, 1917.

SAMUEL TROOID, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOB. T WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ieUn-REr/rovma MACHINE.

inmate.

Specification of Letters Patent.

Patented Dec. d, fwl'tt I To all whom it may concern:

Be it known that I, SAMUEL TROOD, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Bur-Removing Machines, of which the following is a specification.

My invention relates to the shaping and finishing of punched laminations and other metallic objects, and it has particular reference to means whereby burs formed upon sheared edges of punchings may be conveniently and expeditiously removed without distorting the punchings.

Laminations, as used extensively in the manufacture of electrical apparatus, are punched from thin sheets of metal by means of suitable punch presses. The most satisfactory punchings are made When the shearing operation is effected by means of tools having cutting edges which operate at angles with one another. But, inasmuch as the usual punch presses embody tools having co-acting sharp edges which operate in parallelism, it is essential that the edges of the tools be maintained sharp at all times in order to prevent the forming of burs upon the sheared edges of the laminations. If the cutting edges become slightly worn or dulled, a perfect shearing is not elfected, and the material comprising the laminations is distorted in the form of burs.

Burs have saw-tooth edges that vary in height according to the condition of the cutting edges of the tools and the grain of the metal sheets from which the laminations are punched. It is particularly desirable that the burs be removed from the laminations before they are assembled in order to permit the laminations to be packed together very closely. Again, the removal of the burs precludes tearing the insulation upon the coils which engage the teeth of the built up core structure composed of the laminations.

\ I-Ieretofore, it has been attempted to remove burs from laminations by grinding, rolling or pressing operations. In the grinding process, only a portion of the burs may be removed, and the laminations may be unevenly ground, especially if they are slightly distorted. Only laminations of special and simple designs may be placed between rollers which flatten the burs but do not remove utilized with equal effectiveness and convenience for removing burs from laminations of small area and simple design. Again, my invention efiects the satisfactory removal of burs from laminations punched from comparatively thin, as well as from comparatively thick, metal sheets.

For a better understanding of the nature and scope of my invention, reference may be had to the following description and the accompanying drawings of which Figures 1 and 2 are front and side views, respectively, of a machine employing a device of my invention arranged to remove burs from laminations; Fig. 3 is a side view showing in detail a portion of my device; Fig. 4: is a partially sectional end view of the device of Fig. 3; Fig. 5 is a plan view of a lamination which is to be operated upon by a machine embodying my invention, and Fig.

'6 is an enlarged view, taken along the line AB, of Fig. 5 and designed to show the nature of a bur which is formed upon sheared edges of a punching.

Referring to the drawings, a high-speed electric motor 1, bolted to a bed plate 2, is provided with a shaft 3 to which is secured a device 4 constructed in accordance with my invention. The free end of the shaft 3 is supported in a bearing 5 which is firmly secured to the bed plate 2. A table 6, pivotally secured to a bracket 7, is disposed directly underneath the bur remover 4 and is longitudinally adjustable on the bed plate 2. The opposite end of the table engages an adjusting screw 8 by means of which the distance between a face plate 9 of the table 6 and the lowermost portion of the bur remover 4 may be regulated.

Suitably spaced circular end plates 10 are rigidly mounted upon the extended shaft 3 of the motor 1 and are connected together by a plurality of parallel rods 11 that are cirin Figs. 3. and 1.

cumferentially disposed about the shaft and are rigidly secured to the plates by means of nuts 12"The'rods are uniformly spaced, and each of them is provided with a plurality of tubular members 13. The members 13 loosely embrace the rods 11 and are preferably made of hardened steel to enhance their effectiveness when they impinge against the lamination burs, as will be hereinafter explained.

Spacers lt, provided with radially ex tending fingers 15, are interposed between adjacent members 13, substantially as shown It is particularly desirable that the members 13 loosely engage the rods 11 so that, when the device a is rotated at a highspeed, and the centrifugal force thereby created tends to throw the members away from the axisof'rotation, they will engage therods 11 as shown in the cross sectional portion of'Fig. l; To'accomplish this, the spacers 1 1 are designed to permit the free radial movement of the members 13 to the'positi'ons shown, while, at the same time, the members arep-revented from moving any substantial distance longitudinally alon the rods 11. Open spaces 16, which are formed between alined members 13, by reason of the inter-position of the spacers 14:, are bridged by other members 13 that are properly disposed upon the rods 11 adjacent thereto.

In order to explain the operation of my device, a lamination 17 is taken which has previously been punched in a press to form slots 18. Upon sheared edges 19, which constitute the sides of the slots 18, are formed burs 20 which are the result of the imperfect shearing operation performed by the punch press. As before mentioned, it is desirable that these burs 20 be removed before the laminations are assembled'to form a magnetic core structure.

The table'6 is adjusted by means of the screw 8 to permit the easy-insertion of the lamination 17 between the cooperating faces of the plate 9and the lowermost member 13 of the device 4. The shaft 3 and the device 4 are then rotatedat a relatively high speed by means of the electric motor 1 or any other suitable power device. After full speedof the device 4; has been attained, the operator, firmly grasping the lamination 17, places it between the face plate 9 and the device t with theburs 20 projecting upwardly. This permits the members 13 to impinge intermittently, in rapid succession, upon the burs 20, thereby effecting their removal Without distorting the material of the lamination 17. Successive portions of the sheared edges 19 of the lamination are progressively brought into contact with the members 13 to eflect removal of the burs 20.

Because of the manner in which the members 13 aresecured to the device 4:, they rebound from the lamination 17 without distorting it. At the same time, considerable momentum is imparted to each member 13 by reason of its high rate of revolution, and the rapid and successive impacts of the members against a bur 20 is sullicient to cause its removal from the lamination along a substantially clean-cut lino. Because the members 13 are of relatively small mass, and because each row comprises a plurality of them, it is apparent that, when the device i is rotated at a high speed, each longitudinal row of members becomes more or less flexible, which permits some members to rebound from still burs while other mem- 'bers in the same row impinge upon the less tenacious burs, thereby effecting their removal in a comparatively short time. inasmuch as a relatively great number of in termittent impacts may be imparted per unit of time against the stiff burs, it is obvious that only a short interval of time is re quired to remove the burs from the lamination without distorting it.

In a device which I have constructed, the mean diameter is substantially 6 inches. Around the circumference are disposed twelve members 13, the outside diameter of each member being substantially 11 inches, the inside diameter being substantially 5, inch, and the length being substantially one inch. To remove the burs from the laminations most satisfactorily, I find it is desirable to rotate the device at speeds varying from 750 to 6,000 revolutions per minute, according to the conditions obtaining. If burs are formed upon intricately designed punchings in which only a small amount of material extends between adjacent slots, a high speed is preferable, and it is desirable that the members 13 strike comparatively light impacts. For large burs or for burs formed upon coarse-grained material, it is preferable to rotate the device 4 at a comparatively slow speed and to permit the members 13 to strike comparatively heavy impacts.

Those skilled in the art will readily undertand that my device is not restricted to the specific construction hereinbefore shown and described. Obviously, other devices may be made without departing from the spirit of my invention, and I desire that all such modifications shall be included within its scope.

I claim as my invention:

1. A rotatable device for removing burs which comprises spaced end plates, a plurality of circumferentially disposed parallel rods extending between the end plates, and

tubular members disposed upon the rods and loosely embracing the same.

2. A device for treating metallic sheets comprising spaced rotatable end plates, a rod extending between said end plates, and

maame a tubular member loosely mounted upon said rod.

3. A device for treating metallic sheets comprising rotatable spaced end plates, parallel rods supported by the end plates and circumferentially disposed relative to their axis of rotation, a plurality of tubular members disposed upon each rod and loosely embracing the same, and spacers interposed between adjacent tubular members.

4:. A device for treating metallic sheets comprising spaced end plates, parallel rods supported by the end plates and circumferentially disposed about their axis of rotation, and a row of spaced members loosely mounted upon each of said rods, the members in one row alternating With the spaces of the adjacent rows.

In testimony whereof, I have hereunto subscribed my name this 16th day of Feb, 1914.

SAMUEL TROOD.

Witnesses:

J. J. MCCLURE, B. B. HINEs.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

